Synthesis, characterization and template removal of an iron-containing aluminophosphate molecular sieve with LAU topology

Iron(II)-substituted LAU-zeotype aluminophosphate molecular sieve (denoted as FeAPO-LAU) was synthesized successfully by using imidazole as template in the solvothermal system. The detemplation process was studied to elucidate the stability and microporous characteristics of FeAPO-LAU. In situ temperature-dependent X-ray diffraction analyses indicated that the framework of FeAPO-LAU possessed higher thermal stability and maintained the framework integrity until 923 K. The organic templates could be removed by stage-temperature-programmed calcination using lower heating rate in O2 atmosphere, which gave rise to the sample with surface areas of ca. 105 m2/g. NH3-temperature programmed desorption (NH3-TPD) analysis showed that detemplated FeAPO-LAU had a weak acidity. Magnetic measurement revealed that both as-synthesized and detemplated FeAPO-LAU showed antiferromagnetic behaviour.

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► A new FeAPO-LAU molecular sieve with Fe/Al ratio of 2 has been synthesized by using imidazole as template.
► Detemplation process has been studied by stage-temperature-programmed calcinations.
► Detemplated FeAPO-LAU (623 and 753 K) sample has accessible pores and a weak acidity.